1/*
2 * Touchkey driver for Freescale MPR121 Controllor
3 *
4 * Copyright (C) 2011 Freescale Semiconductor, Inc.
5 * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
6 *
7 * Based on mcs_touchkey.c
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 */
14
15#include <linux/module.h>
16#include <linux/input.h>
17#include <linux/i2c.h>
18#include <linux/slab.h>
19#include <linux/delay.h>
20#include <linux/bitops.h>
21#include <linux/interrupt.h>
22#include <linux/i2c/mpr121_touchkey.h>
23
24/* Register definitions */
25#define ELE_TOUCH_STATUS_0_ADDR	0x0
26#define ELE_TOUCH_STATUS_1_ADDR	0X1
27#define MHD_RISING_ADDR		0x2b
28#define NHD_RISING_ADDR		0x2c
29#define NCL_RISING_ADDR		0x2d
30#define FDL_RISING_ADDR		0x2e
31#define MHD_FALLING_ADDR	0x2f
32#define NHD_FALLING_ADDR	0x30
33#define NCL_FALLING_ADDR	0x31
34#define FDL_FALLING_ADDR	0x32
35#define ELE0_TOUCH_THRESHOLD_ADDR	0x41
36#define ELE0_RELEASE_THRESHOLD_ADDR	0x42
37#define AFE_CONF_ADDR			0x5c
38#define FILTER_CONF_ADDR		0x5d
39
40/*
41 * ELECTRODE_CONF_ADDR: This register configures the number of
42 * enabled capacitance sensing inputs and its run/suspend mode.
43 */
44#define ELECTRODE_CONF_ADDR		0x5e
45#define ELECTRODE_CONF_QUICK_CHARGE	0x80
46#define AUTO_CONFIG_CTRL_ADDR		0x7b
47#define AUTO_CONFIG_USL_ADDR		0x7d
48#define AUTO_CONFIG_LSL_ADDR		0x7e
49#define AUTO_CONFIG_TL_ADDR		0x7f
50
51/* Threshold of touch/release trigger */
52#define TOUCH_THRESHOLD			0x08
53#define RELEASE_THRESHOLD		0x05
54/* Masks for touch and release triggers */
55#define TOUCH_STATUS_MASK		0xfff
56/* MPR121 has 12 keys */
57#define MPR121_MAX_KEY_COUNT		12
58
59struct mpr121_touchkey {
60	struct i2c_client	*client;
61	struct input_dev	*input_dev;
62	unsigned int		key_val;
63	unsigned int		statusbits;
64	unsigned int		keycount;
65	u16			keycodes[MPR121_MAX_KEY_COUNT];
66};
67
68struct mpr121_init_register {
69	int addr;
70	u8 val;
71};
72
73static const struct mpr121_init_register init_reg_table[] = {
74	{ MHD_RISING_ADDR,	0x1 },
75	{ NHD_RISING_ADDR,	0x1 },
76	{ MHD_FALLING_ADDR,	0x1 },
77	{ NHD_FALLING_ADDR,	0x1 },
78	{ NCL_FALLING_ADDR,	0xff },
79	{ FDL_FALLING_ADDR,	0x02 },
80	{ FILTER_CONF_ADDR,	0x04 },
81	{ AFE_CONF_ADDR,	0x0b },
82	{ AUTO_CONFIG_CTRL_ADDR, 0x0b },
83};
84
85static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
86{
87	struct mpr121_touchkey *mpr121 = dev_id;
88	struct i2c_client *client = mpr121->client;
89	struct input_dev *input = mpr121->input_dev;
90	unsigned int key_num, key_val, pressed;
91	int reg;
92
93	reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
94	if (reg < 0) {
95		dev_err(&client->dev, "i2c read error [%d]\n", reg);
96		goto out;
97	}
98
99	reg <<= 8;
100	reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
101	if (reg < 0) {
102		dev_err(&client->dev, "i2c read error [%d]\n", reg);
103		goto out;
104	}
105
106	reg &= TOUCH_STATUS_MASK;
107	/* use old press bit to figure out which bit changed */
108	key_num = ffs(reg ^ mpr121->statusbits) - 1;
109	pressed = reg & (1 << key_num);
110	mpr121->statusbits = reg;
111
112	key_val = mpr121->keycodes[key_num];
113
114	input_event(input, EV_MSC, MSC_SCAN, key_num);
115	input_report_key(input, key_val, pressed);
116	input_sync(input);
117
118	dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
119		pressed ? "pressed" : "released");
120
121out:
122	return IRQ_HANDLED;
123}
124
125static int mpr121_phys_init(const struct mpr121_platform_data *pdata,
126				      struct mpr121_touchkey *mpr121,
127				      struct i2c_client *client)
128{
129	const struct mpr121_init_register *reg;
130	unsigned char usl, lsl, tl, eleconf;
131	int i, t, vdd, ret;
132
133	/* Set up touch/release threshold for ele0-ele11 */
134	for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
135		t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
136		ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
137		if (ret < 0)
138			goto err_i2c_write;
139		ret = i2c_smbus_write_byte_data(client, t + 1,
140						RELEASE_THRESHOLD);
141		if (ret < 0)
142			goto err_i2c_write;
143	}
144
145	/* Set up init register */
146	for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
147		reg = &init_reg_table[i];
148		ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
149		if (ret < 0)
150			goto err_i2c_write;
151	}
152
153
154	/*
155	 * Capacitance on sensing input varies and needs to be compensated.
156	 * The internal MPR121-auto-configuration can do this if it's
157	 * registers are set properly (based on pdata->vdd_uv).
158	 */
159	vdd = pdata->vdd_uv / 1000;
160	usl = ((vdd - 700) * 256) / vdd;
161	lsl = (usl * 65) / 100;
162	tl = (usl * 90) / 100;
163	ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
164	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
165	ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
166
167	/*
168	 * Quick charge bit will let the capacitive charge to ready
169	 * state quickly, or the buttons may not function after system
170	 * boot.
171	 */
172	eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
173	ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
174					 eleconf);
175	if (ret != 0)
176		goto err_i2c_write;
177
178	dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
179
180	return 0;
181
182err_i2c_write:
183	dev_err(&client->dev, "i2c write error: %d\n", ret);
184	return ret;
185}
186
187static int mpr_touchkey_probe(struct i2c_client *client,
188			      const struct i2c_device_id *id)
189{
190	const struct mpr121_platform_data *pdata =
191			dev_get_platdata(&client->dev);
192	struct mpr121_touchkey *mpr121;
193	struct input_dev *input_dev;
194	int error;
195	int i;
196
197	if (!pdata) {
198		dev_err(&client->dev, "no platform data defined\n");
199		return -EINVAL;
200	}
201
202	if (!pdata->keymap || !pdata->keymap_size) {
203		dev_err(&client->dev, "missing keymap data\n");
204		return -EINVAL;
205	}
206
207	if (pdata->keymap_size > MPR121_MAX_KEY_COUNT) {
208		dev_err(&client->dev, "too many keys defined\n");
209		return -EINVAL;
210	}
211
212	if (!client->irq) {
213		dev_err(&client->dev, "irq number should not be zero\n");
214		return -EINVAL;
215	}
216
217	mpr121 = devm_kzalloc(&client->dev, sizeof(*mpr121),
218			      GFP_KERNEL);
219	if (!mpr121)
220		return -ENOMEM;
221
222	input_dev = devm_input_allocate_device(&client->dev);
223	if (!input_dev)
224		return -ENOMEM;
225
226	mpr121->client = client;
227	mpr121->input_dev = input_dev;
228	mpr121->keycount = pdata->keymap_size;
229
230	input_dev->name = "Freescale MPR121 Touchkey";
231	input_dev->id.bustype = BUS_I2C;
232	input_dev->dev.parent = &client->dev;
233	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
234
235	input_dev->keycode = mpr121->keycodes;
236	input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
237	input_dev->keycodemax = mpr121->keycount;
238
239	for (i = 0; i < pdata->keymap_size; i++) {
240		input_set_capability(input_dev, EV_KEY, pdata->keymap[i]);
241		mpr121->keycodes[i] = pdata->keymap[i];
242	}
243
244	error = mpr121_phys_init(pdata, mpr121, client);
245	if (error) {
246		dev_err(&client->dev, "Failed to init register\n");
247		return error;
248	}
249
250	error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
251				     mpr_touchkey_interrupt,
252				     IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
253				     client->dev.driver->name, mpr121);
254	if (error) {
255		dev_err(&client->dev, "Failed to register interrupt\n");
256		return error;
257	}
258
259	error = input_register_device(input_dev);
260	if (error)
261		return error;
262
263	i2c_set_clientdata(client, mpr121);
264	device_init_wakeup(&client->dev, pdata->wakeup);
265
266	return 0;
267}
268
269#ifdef CONFIG_PM_SLEEP
270static int mpr_suspend(struct device *dev)
271{
272	struct i2c_client *client = to_i2c_client(dev);
273
274	if (device_may_wakeup(&client->dev))
275		enable_irq_wake(client->irq);
276
277	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
278
279	return 0;
280}
281
282static int mpr_resume(struct device *dev)
283{
284	struct i2c_client *client = to_i2c_client(dev);
285	struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
286
287	if (device_may_wakeup(&client->dev))
288		disable_irq_wake(client->irq);
289
290	i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
291				  mpr121->keycount);
292
293	return 0;
294}
295#endif
296
297static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
298
299static const struct i2c_device_id mpr121_id[] = {
300	{ "mpr121_touchkey", 0 },
301	{ }
302};
303MODULE_DEVICE_TABLE(i2c, mpr121_id);
304
305static struct i2c_driver mpr_touchkey_driver = {
306	.driver = {
307		.name	= "mpr121",
308		.owner	= THIS_MODULE,
309		.pm	= &mpr121_touchkey_pm_ops,
310	},
311	.id_table	= mpr121_id,
312	.probe		= mpr_touchkey_probe,
313};
314
315module_i2c_driver(mpr_touchkey_driver);
316
317MODULE_LICENSE("GPL");
318MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
319MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
320